- Real name: Gayle Marsh
- Occupation: Student at Chicago's Lake Shore University
- Known Relatives: Unnamed Parents (deceased)
- Group Affiliation: None
- Base of Operations: Chicago, Illinois
- Height: 5'3"
- Weight: 103 lbs.
- Eyes: Blue
- Hair: Black
Born in the Chicago suburb of Skokie, Illinois, Gayle Marsh had a fairly normal and undistinguished childhood until, at the age of twelve, she began to exhibit signs of extraordinary psychic powers. Her parents were frightened by their daughter's burgeoning powers and abilities, and at the suggestion of their family doctor, turned Gayle over to the more experienced hands at the Institute for Higher Psychokinetic Study, a Chicago-based research facility that specializes in the study of extrasensory phenomena.
The researchers at the Insitute, excited at the opportunity to study Gayle, found her telekinetic powers to be among the most powerful ever recorded. One researcher in particular, Doctor Daniel Pendergast seemed to find Gayle's powers particularly fascinating, and a friendship bwteen the two quickly developed. Gayle was initially only supposed to spend a week at the Institute, but during her stay there, her parents were killed in a traffic accident. As Gayle had no other family to take her in, Pendergast petitioned the courts and was soon after made the girl's legal guardian.
Under Pendergast's charge, Gayle was taught how to develop and use her great psychic powers. Pendergast had plans for Gayle to help him to fight a grave menace that he believed held the world in it's sway. He saw something that he called "decay" affecting everything and everyone, stripping the world of order and anything that was good. In Gayle, he saw the perfect warrior who was capable of battling and defeating these forces of decay.
By the time that Gayle entered college at Chicago's Lake Shore University, her powers had reached their peak, and Pendergast decided that it was time that the battle against decay be joined. Gayle, hesitant to take up the fight, fears that the emotional backlash from her intended victims will be too painful for her to handle due to her being a "sensitive"—a receiver of emotions of others.
After a frightening encounter of the campus of Lake Shore University, Gayle is unleashed upon Chicago when she sesnses the presence and power of Supergirl, and mistook her for an agent of the decay. Working under the name of Psi, Gayle demonstrates a startlingly high degree of power in her battles with Supergirl, actually fighting the Maid of Might to a standstill. However, Psi's reluctance to kill her was obvious and Supergirl takes advantage of this by playing upon the girl's fears. Trapped between the telepathic urgings of Pendergast and the logical arguments put forth by Supergirl, Psi's fragile emotional states collapses and she flees in panic from her mission.
Disappointed by her showing and believing that she has gone over to the side of decay, Pendegast sees it as his duty to kill Gayle. Though confused, Psi is still able to act in self-defense and strike out to save herself. The result of this is that Pendergast is transformed into the living manifestation of his own worst fears, becoming Decay, a creature whose very touch can decay and rot virtually any and all matter. Psi eventually sees the error of her training and removes both herself and the persona of Decay from the world. Both Psi and Decay have not been seen since (DNAS No. 1, Nov 1982: "A Very Strange and Special Girl"; DNAS No. 2, Dec 1982: "Crisis over Chicago!"; DNAS No. 3, Jan 1983: "Decay Day!").
Powers and Abilities
As Psi, Gayle Marsh's psychokinetic powers allow her to tap into the unused potential of her mind. Manifesting great strength, Psi's powers have never been tested under controlled conditions to determine their exact limits.